1. Field of the Invention
This invention relates to tap assemblies through which liquid commodities are dispensed by gravity flow from flexible plastic containers of bag-in-a-box packaging and more particularly is directed to the assembly of a spout for the container fitted with a dispenser closure as a spigot valve molded of elastomeric plastic resins and equipped with an interior gas impermeable barrier.
2. Description of the Prior Art
In recognition of the adverse effect on shelf life of liquid products packaged in bag-in-a-box containers due to gas permeability of elastomeric plastic materials providing the required resiliency for valve operation in dispenser closures used on gravity flow dispensing spouts, my previous patent, entitled Dispenser Closure, granted Feb. 18, 1986 as U.S. Pat. No. 4,570,826, discloses a two-piece dispenser closure as the spigot valve and a gas impermeable barrier formed as a dislodgeable cap positioned across the inner end of the tubular spout.
My U.S. Pat. No. 3,400,866 discloses a unitary dispenser closure therein described as an integral closure and valve member comprising a tubular skirt which snaps onto the spout and a deeply concave diaphragmic transverse wall extending into the spout and engaging the lip of the latter to provide the sealing closure. The skirt has an opening forming a delivery port which communicates with the interior of the spout when the diaphragmic wall is distorted by toggle action of a finger manipulative tab projecting from a central region of the wall thereby resiliently disengaging a portion of the wall from its sealing engagement with the lip of the spout. The diaphragmic action closes the seal upon the toggle release. U.S. Pat. No. 3,972,452 to W. C. Welsh and U.S. Pat. No. 4,211,348 to W. R. Scholle disclose other diaphragmic toggle release constructions.
A need appears to exist for tap assemblies incorporating improved dispenser closures which will provide the simplicity of my said unitary closure and the gas impermeability of my two-piece construction disclosed in Pat. No. 4,570,826.